Many biological and chemical applications require instant mixing of two or more buffers to generate a suitable solution. Normally different buffers are mixed in a mixer chamber, and transferred to one or more reaction containers after mixing. The ratio of input buffers is generally controlled by adjusting the incoming flow rate of the buffers.
While mixing of buffers is a somewhat standard process, current systems are incapable of offering a flexible solution. When the experimental needs call for a small amount of a solution, a small mixer chamber is desirable than a larger one, to reduce dead volume, it is also more cost effective since it reduces buffer waste. On the other hand, when a large amount of solution is needed, a small chamber would not be able to fulfill the job. For example, the ÄKTA™ systems have to use three different sized mixer chambers (i.e., 0.6 ml, 1.4 ml and 5 ml). The 0.6 ml mixer chamber shall be used if the required output flow rates <2 ml/min, the 1.4 ml one for flow rates between 2 and 12 ml/min, while the 5 ml one for flow rates between 12 and 25 ml/min. Thus the mixer chamber has to be swapped when the desired flow rate changes. Due to this complication, the mixer chamber can not be integrated to the mixer module (stirrer).
There is a need for an integrated mixer chamber design which adjusts the volume in response to an input flow rate. It is also desirable to simplify the mixer module design and improve the homogeneity of solution produced.